Ruptured isolated spinal artery aneurysms: a rare manifestation of an arterial dissecting disease

Abstract

Isolated spinal artery aneurysms (ISAAs) are a rare cause of intracranial and spinal hemorrhages with unclear pathophysiology and natural history and non-standardized management strategies. We hereby present two cases of ruptured ISAAs of posterior spinal arteries treated with open surgery and embolization, respectively. Case presentations are followed by a comprehensive literature review on ISAA pathophysiology, natural history, and management strategies.

Keywords: arterial dissection; spinal aneurysm; spinal dissection; spinal hemorrhage; spinal vascular malformation.

Figure 1

A 60-year-old woman presented with acute back pain and flaccid quadriparesis. A, B: Sagittal T2-weighted MRI images of the spine [(A) cervical spine and (B) thoracic spine] show a subdural hematoma extending along the lower cervical and upper thoracic spine, and spinal subarachnoid hemorrhage extending down to the level of T9. Note associated cord edema. (D, E) Axial T2-weighted (D) and gradient echo (E) images demonstrate the SDH centered predominantly along the right side of the spinal canal (arrowheads), displacing the cord to the left. (F) Postcontrast T1-weighted image shows focal nodular enhancement within the subdural hematoma (arrow), corresponding to a fusiform “tent-like” dissecting aneurysm arising from the right T2 radiculopial artery on spinal angiogram (C, arrow). This was surgically resected and characterized by histology as an organizing hematoma.

Figure 2

A 66-year-old woman on warfarin presented with acute severe low back pain. (A, B, D) T2-weighted MRI images demonstrate conus edema (long arrow) with spinal subdural hematoma, predominantly on the left, displacing the conus to the right (arrowheads). Note the lateral compression of the spinal cord and cerebrospinal fluid by the hematoma (long arrowhead). (C, E) Contrast-enhanced MRI shows focal nodular enhancement at the left peripheral aspect of the cord at the T12 level (short arrow), confirmed later on angiogram as a ruptured left T12 posterior spinal artery dissecting aneurysm (Figure 3A).

Figure 3

Same patient as in Figure 2. (A) Left T12 intersegmental artery (ISA) angiogram demonstrates an oval-shaped dissecting pseudoaneurysm arising from a posterior spinal artery (white arrowhead). (B) Right T12 ISA angiogram postcoil embolization of the left T12 ISA shows retrograde filling of the pseudoaneurysm through retrocorporeal collaterals (black arrowhead). (C) Unsubtracted image of the T12 vertebral body demonstrates coil and n-butyl cyanoacrylate occlusion of bilateral T12 ISAs. (D) Repeat T12 ISA angiogram obtained after the deterioration of the patient 2 weeks after the first embolization shows no filling of the treated aneurysm and a new arteriovenous shunting between the right T12 ISA and the Azygos vein (arrow). This was considered to be incidental and unrelated to the patient's clinical deterioration, but nevertheless embolized via n-butyl cyanoacrylate injection.